The present invention relates to an apparatus for controlling water flow, namely a novel electronic water controller capable of operation using a battery-type power source. Currently available water controllers are mechanically operated and some applications can be powered using alternating current and direct current.
Typically, water controllers are used in two primary applications. The first application is in water systems comprising a water overflow reservoir. An example of this application can be found in grocery stores. In grocery stores it is common to use refrigerators and freezers, as well as water “spritzers” used to keep produce fresh. Refrigerators and freezers generate condensate, and spritzers generate run-off water. Excess water in the form of condensate and run-off is generally collected in a reservoir, the reservoir typically being open to the atmosphere. The reservoir is typically functionally connected to a vacuum source via an external vacuum-operated valve that is controlled by a water controller. When the excess water within the reservoir exceeds a predetermined volume level, the water controller releases the vacuum to the external valve. The valve opens to allow vacuum pressure to evacuate the water from the reservoir to a collection tank for disposal.
The second type of application in which water controllers are often used is that of toilet systems, especially, but not limited to, toilet systems in institutional buildings, high-rise buildings, ships and the like. In these settings, space is at a premium and vacuum systems provide great flexibility in addressing limited availability of space. In such toilet systems, the actuation of the vacuum is accomplished by different means than in first type of application described above. In toilet systems, typically, the controllers are actuated by a user, either manually by pushbutton or flush handle, or through user movement registered via electric eye apparatus. The underlying water control is common, however, and once actuated the controller releases vacuum in order to evacuate the water and sewage into a holding tank to await disposal.
Currently available mechanical water controllers have inherent weaknesses. When waste or excess water within the reservoir exceeds a predetermined volume level, the water exerts pressure on a diaphragm inside the controller, the pressure being proportional to the height of water within the reservoir. The pressure causes the diaphragm to switch to an “On” position. In this state, vacuum from a vacuum source evacuates a timing chamber internal to the controller and a pilot valve opens and applies vacuum to a main valve. The main valve opens and releases vacuum pressure to the reservoir, thereby evacuating the water from the reservoir. Duration of pilot valve opening is controlled by the decay of vacuum within the internal timing chamber. This decay is in turn controlled by a needle valve that controls the rate of airflow into the timing chamber. The air entering into the chamber increases air pressure in the chamber, thereby reducing vacuum. When the pressure within the timing chamber reaches zero, the pilot valve and the diaphragm reset to the “Off” position.
While mechanical controllers are advantageous owing to their ease of use and low cost, they have several disadvantages that result in decreased reliability, stability and durability. First, mechanical controllers are inherently imprecise. Owing to their dependence upon vacuum pressure levels to regulate duration of remaining in the “On” position, variations in vacuum pressure can result in durations that are too long and too short. If vacuum is too high (lower pressure), the duration will be too long, thus wasting vacuum capacity and risking damage to the water control system. Conversely, when the vacuum is too low (higher pressure), the duration will be too short resulting in inadequate evacuation of water from the reservoir. Additionally, inherent inaccuracies in the measurement of water and system pressures can result in the controller pilot switch being in the “On” position when vacuum is too low (higher pressure).
Second, timing mechanisms in mechanical controllers are inherently unstable because the needle valves are prone to shift during use and transport. Dirt and other particles can accumulate on and occlude the needle valve thereby reducing airflow through the valve. In this scenario the reduced airflow results in longer timing and the controller remaining in the “On” position too long. If the needle valve becomes totally occluded the controller can get stuck in the “On” position resulting in catastrophic failure of the controller and water system.
Third, mechanical controllers offer slow response to changes in vacuum pressure. If vacuum pressure drops rapidly, for example after a power outage, individual mechanical controllers must respond by immediately switching to the “Off” position in order to allow the vacuum source to reduce the system pressure (i.e., increase the vacuum) to a predetermined level.